The US Department of Justice has appointed former FBI chief as special counsel to oversee the investigation of alleged Russian efforts to affect the 2016 election in favour of the US President Donald Trump.

Robert Mueller, 72, is a Vietnam veteran and former US attorney who ran the FBI from 2001-2013, Efe reported on Thursday.

The appointment was announced by Deputy Attorney General Rod J. Rosenstein, who has authority over the Russia probe due to the decision of Attorney General Jeff Sessions’ decision to recuse himself because of his role in the Trump campaign.

“My decision is not a finding that crimes have been committed or that any prosecution is warranted. I have made no such determination,” Rosenstein said.

“What I have determined is that based upon the unique circumstances, the public interest requires me to place this investigation under the authority of a person who exercises a degree of independence from the normal chain of command,” he said.

Rosenstein is one of the few senior figures in the Trump administration to enjoy the confidence of both Republican and Democratic lawmakers.

“Special Counsel Mueller will have all appropriate resources to conduct a thorough and complete investigation, and I am confident that he will follow the facts, apply the law and reach a just result,” the deputy attorney general said.

Mueller has agreed to resign from his private law firm to allay concerns about potential conflicts of interest.

The naming of Mueller as special counsel comes a week after Trump abruptly fired the man who succeeded him as FBI director, James Comey.

While the official announcement of Comey’s dismissal cited his handling of the investigation into Hillary Clinton’s use of a private e-mail server during her 2009-2013 tenure as secretary of state, Democrats accused Trump of seeking to short-circuit the probe of possible collusion between his team and the Russian government.

Senators plan to question Rosenstein about Comey’s firing when the deputy attorney general testifies Thursday in a closed hearing